Good gas mileage is possible on an Ultra. How do I know? I did it.
Riding two up from Tonopah NV to Caliente NV, highway 375. It is 194 miles between gas stations and when I got to Caliente it took 4.1 gallons. I kept it under 65 and eased on the throttle and made it work.
So, 50 MPG is possible if you take it easy. If you can't, don't ride that road. It is a long open nothing with little traffic.
Oh, this was without the sidecar on, wouldn't have made it with that on there.

 

I regularly get mid 40s...and that's without "taking it easy". I believe 50 is possible on mine as well.

 

Where's the fun in taking it easy? No matter how hard I try I ain't ever going to get good mileage on my scoot.

 

Whitefish, MT to Choteau, MT in July this year, 2 up loaded average 60 to 65 mph. I put 3.4 gallons in at Choteau with 175 miles on the trip odometer. Thats 51.4 mpg.

 

I get between 45 and 48 on my RKC, but that's really not the point. I don't ride to save gas, and to be honest, I'd keep riding if gas cost twice as much and I only got half the mileage.

 

Me too and mines a 94! You can go about 70 before it starts to drop down. At a hundie, you get 40.

 

I recently traveled to Florida on my 08 Ultra. I KNOW that 50+ mpg is possible, cause I averaged 53 mpg for the 3400 mile trip. That was riding one up, with all the gear for me and the wife (she rode her own bike)

I checked MPG at every gas stop, and she averaged 48, and I averaged 53. Thats riding the freeway, with cruise set at 68 mph.

 

Well, I don't ride an Ultra, but....

Sunday I just got 52.8mpg out of my XL1200C after doing my best impression of Valentino Rossi in the local canyons. I was riding it hard, keeping it in the upper limit of the powerband, and I got better mileage than I usually do on the highway. Go figure.